Monofix Nail

ABSTRACT

An intramedullary device includes an intramedullary nail extending along a longitudinal axis from a proximal end to a distal end, the nail including a channel extending longitudinally therethrough and an opening extending laterally through a wall thereof proximate the distal end, the channel including a ramped surface along a distal portion thereof opposite the opening. The device further includes a wire extending along a longitudinal axis from a proximal end to a distal end, the wire sized and shaped to be inserted into the channel of the nail such that the distal end engages the ramped surface to extend through the opening.

PRIORITY CLAIM

The present application is a Divisional Application of pending U.S.patent application Ser. No. 13/523,227 filed on Jun. 14, 2012; whichclaims priority to U.S. Provisional Application Ser. No. 61/500,284filed on Jun. 23, 2011 and U.S. Provisional Application Ser. No.61/531,417 filed on Sep. 6, 2011. The disclosure of the aboveapplications is incorporated herein by reference.

BACKGROUND

Intramedullary nails are inserted into medullary canals of long bones tofix fractures thereof. Once inserted into a medullary canal, anintramedullary nail is generally fixed therein by inserting one or morebone fixation elements through locking holes extending transverselythrough the nail. The curvature of a medullary canal often deviates fromthe initial curvature along which the nail extends so that the nail isdeformed during insertion. This deformation moves the transverse lockingholes away from their expected position making it difficult to drill theholes required to insert the locking screws therein.

SUMMARY OF THE INVENTION

The present invention relates to an intramedullary device, whichincludes an intramedullary nail extending along a longitudinal axis froma proximal end to a distal end, the nail including a channel extendinglongitudinally therethrough and an opening extending laterally through awall thereof proximate the distal end, the channel including a rampedsurface along a distal portion thereof opposite the opening, and a wireextending along a longitudinal axis from a proximal end to a distal end,the wire sized and shaped to be inserted into the channel of the nailsuch that the distal end engages the ramped surface to extend throughthe opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of a device according to an exemplaryembodiment of the present invention;

FIG. 2 shows a longitudinal cross-sectional view of the device accordingto FIG. 1;

FIG. 3 shows a longitudinal cross-sectional view of a portion of anintramedullary nail of the device according FIG. 1;

FIG. 4 shows a longitudinal cross-sectional view of a distal portion ofthe device according to FIG. 1;

FIG. 5 shows an enlarged perspective view of a distal end of a fixationwire extending out of a distal hole of the intramedullary nail,according to the device of FIG. 1;

FIG. 6 shows a perspective view of a distal end of a fixation wireaccording to an alternate embodiment of the present invention;

FIG. 7A shows a longitudinal cross-sectional view of a driving toolcoupled to the fixation wire according to the device of FIG. 1;

FIG. 7B shows a longitudinal cross-sectional view of a removal toolcoupled to the fixation wire according to the device of FIG. 1;

FIG. 8 shows a longitudinal cross-sectional view of a proximal portionof the intramedullary device of FIG. 1;

FIG. 9A shows a longitudinal cross-sectional view of the proximalportion of an intramedullary device including an alternate embodiment ofan end cap;

FIG. 9B shows a perspective view of a first alternate embodiment of theproximal portion of an intramedullary device;

FIG. 9C shows a perspective view of a first alternate embodiment of theproximal portion of an intramedullary device;

FIG. 9D shows a perspective view of a first alternate embodiment of theproximal portion of an intramedullary device;

FIG. 10 shows a longitudinal cross-sectional view of a proximal portionof an intramedullary device according to a further exemplary embodimentof the present invention; and

FIG. 11 shows a longitudinal cross-sectional view of a proximal portionof an intramedullary device according to another exemplary embodiment ofthe present invention.

DETAILED DESCRIPTION

The present invention may be further understood with reference to thefollowing description and the appended drawings, wherein like elementsare referred to with the same reference numerals. The present inventionrelates to bone treatment devices and, in particular, relates to anintramedullary device. Exemplary embodiments of the present inventiondescribe an intramedullary device including an intramedullary nail and afixation wire inserted into a channel of the nail such that a distal endof the wire extends out of a distal hole of the nail. Thus, theintramedullary nail may be fixed to the bone from within the nail viathe wire such that additional incisions and bone drilling are notrequired. It should be noted that the terms “proximal” and “distal,” asused herein refer to a direction toward (proximal) and away from(distal) a surgeon or other user of the device.

As shown in FIGS. 1-9, an intramedullary device 100 comprises anintramedullary nail 102 and a fixation wire 104, which is passed throughthe intramedullary nail 102 to a distal hole 106 including a rampedsurface angled to engage a wire and pass it out of the nail 102 as willbe described in more detail below to fix the nail 102 at a desiredlocation within a bone. The intramedullary nail 102 includes a channel108 longitudinally therethrough such that the distal hole 106 extendsthrough a transverse wall 110 of the nail 102 from an interior of thenail 102 defined by the channel 108 to an exterior of the nail 102. Adistal surface of the distal hole 106 is ramped as described below toengage the distal end of the wire 104 and guide the wire 104 away fromthe longitudinal axis of the nail 102 out of the distal hole 106. Thus,the fixation wire 104 passes through the channel 108 with a distal end112 of the wire 104 exiting the nail 102 via the distal hole 106 angledrelative to a longitudinal axis of the nail 102 to penetrate boneadjacent to the transverse surface of the nail 102 fixing the nail 102within the bone. The wire 104 may include a self tapping end so that thenail 102 may be fixed to the bone from within the nail 102 (i.e.,without requiring the predrilling of a hole to receive the wire). Thus,a location of the distal hole 106 after insertion of the nail 102 intothe bone does not need to be identified and drilled from outside thebody.

A shown in FIGS. 1-4, the intramedullary nail 102 extends along alongitudinal axis from a proximal end 114 to a distal end 116 andincludes the channel 108 extending therethrough along the longitudinalaxis. The distal hole 106 extends transversely through the wall 110proximate the distal end 116. The channel 108 includes a ramped surface118 extending along a portion thereof corresponding to a position of thedistal hole 106 such that when the fixation wire 104 passes through thechannel 108, the distal end 112 of the wire 104 slides along the rampedsurface 118 and is guided through the distal hole 106 to an exterior ofthe nail 102. The distal hole 106 may be elongated along a length of thenail 102 such that the distal end 112 of the wire 104 may easily passtransversely therethrough while also providing sufficient access formanufacturing (e.g., milling) the ramped surface 118. A distal portion120 of the channel 108 distal of the ramped surface 118 and the distalhole 106 may have a smaller diameter than a proximal portion 122 of thechannel 108 proximal of the ramped surface 118 such that the channel 108may still accommodate a guide wire therethrough. In addition, a portion142 of the channel 108 extending about the distal hole 106 may also havea slightly larger cross-section than the proximal portion 122 such thatthe distal end 112 of the wire 104 does not come into contact therewithas it is being driven (e.g., rotated) into the bone. In other words, aportion of the wall 110 surrounding the distal hole 106 may have asmaller thickness that a remaining portion of the wall 110.

The channel 108 may also include a shoulder 154 distally of a proximalopening 152 thereof. The shoulder 154 extends radially inward such thata diameter of the channel 108 proximal of the shoulder 154 is largerthan a diameter distal of the shoulder 154. Thus, as will be describedin further detail below, the shoulder 154 may engage a portion of thewire 104 and/or a portion of a driving tool to prevent the wire 104 frombeing inserted any further distally through the channel 108.

The nail 102 according to this embodiment of the invention includes aproximal locking hole 124 extending through the wall 110 proximate theproximal end 114 of the nail 102. The proximal locking hole 124 extendsthrough the wall 110 along a central axis angled with respect to thelongitudinal axis of the nail 102. The proximal locking hole 124 opensto a chamber formed at a proximal end of the nail 102 so that it isaccessible from a proximal opening 152 of the channel 108 at theproximal end 114 so that a bone fixation element 126 may be through theproximal locking hole 124 via the proximal opening 152 so that a shaft128 of the bone fixation element 126 extends into the bone surroundingthe channel 108. Thus, the shaft 128 of the bone fixation element 126extends out of the nail 102 into the bone along the central axis of theproximal locking hole 124, at an angle relative to the longitudinal axisof the nail 102. An interior surface of the proximal locking hole 124may be threaded to engage a threading of a head portion of the bonefixation element 126 to lock the bone fixation element 126 in a desiredposition in the nail 102 as would be understood by those skilled in theart.

The nail 102 may additionally include conventional locking holesextending transversely through the nail 102 to receive additional bonefixation elements therethrough. For example, the nail 102 may include aconventional locking hole 130 extending transversely through a proximalor distal portion of the nail 102. The conventional locking holes 130may be located using conventional aiming arms known in the art so that acorresponding hole may be pre-drilled into the bone for the insertion ofadditional bone fixation elements therethrough, as would be understoodby those of skill in the art. It will also be understood by those ofskill in the art, that a hole may also be pre-drilled into the bone tocorrespond to the proximal locking hole 124. Alternatively, the bonefixation element 126 may include a self-drilling tip.

The intramedullary device 100 may further comprise an end cap 150couplable to the proximal end 114 of the intramedullary nail 102 toclose the proximal opening 152 of the channel 108. The end cap 150 maybe received within the proximal opening 152 and threadedly engaged orotherwise locked therein. The end cap 150 may thus include an engagementstructure such as, for example, a hexagonal recess, for engaging aninstrument which drives the end cap 150 into the proximal opening 152.In a further embodiment, as shown in FIG. 9A, an end cap 150′ may besubstantially similar to the end cap 150 but further includes a distallyextending portion 151′ such that when the end cap 151′ is receivedwithin the proximal opening 152, the portion 151′ prevents the wire 104from moving proximally relative to the nail 102.

The wire 104 extends through the opening 152 into the channel 108 andpasses therethrough along the longitudinal axis of the nail 102. Theramped portion 118 of the channel 108 is formed on a side of the channel108 opposite the distal hole 106 and angled toward the distal hole 106so that, as the distal end 112 engages the ramped portion 118, thedistal end of the wire 104 passes into the distal hole 106. As indicatedabove, the distal end 112 may include a self-drilling tip 134 (shown inFIG. 5) so that as the wire 104 passes out of the nail 102, theself-drilling tip 126 permits the distal end 112 to be inserted into thesurrounding bone. A diameter of the distal end 112 of the wire 104 maybe larger than a diameter of a remaining length of the wire 104 suchthat a natural inflection point is formed along the wire 104 at theplace where the distal end 112 meets the remaining length of the wire104. For example, the distal end 112 may have a diameter ofapproximately 4.0 mm while the remaining length of the wire 104 has adiameter of approximately 3.2 mm. Thus, when the distal end 112 comesinto contact with the ramped portion 118, the distal end 112 bends atthis inflection point so that it is angled toward the distal hole 106such that the distal end 112 extends through the hole 106 and into thesurrounding bone. In another embodiment, as shown in FIG. 6, a wire 104′has a distal end 112′ including a threaded conical tip 136′ in additionto a self-drilling portion 134′ immediately proximal thereto to provideimproved engagement with the bone and increase a fixation stabilitythereof.

As shown in FIG. 7A, the proximal end 132 of the wire 104 according tothis embodiment includes an engagement portion 138 sized and shaped toengage a portion of a driving tool 145 which may be used to rotate thewire 104 to drive the distal end 112 of the wire 104 distally throughthe distal hole 106 and into bone. The engagement portion 138 may be,for example, hexagonal to engage a corresponding hexagonal portion ofthe driving tool 145 or may have any other shape which willnon-rotatably mate with an end of the driving tool, as would beunderstood by those skilled in the art. As shown in FIG. 7B, theproximal end 132 may also include a threaded portion 140 distally of theengagement portion 138 to engage a removal tool 146. The threadedportion 140 includes threading along an outer surface of the wire 102configured to engage corresponding threading 144 along a portion of theremoval tool 146. The removal tool 146 may be, for example, alongitudinal element including threads 144 along an interior surface ofa distal end 148 thereof for coupling to the threaded portion 138 of thewire 104 such that, once the removal tool 146 and the wire 104 arecoupled, the removal tool 146 may be both rotated to rotate the wire 104and pulled proximally to draw the wire 104 proximally. If theself-drilling tip 126 of the wire 104 extends along the distal end 112in a right side orientation (i.e., requiring a right side rotation to bedrilled into the bone) the threads along the threaded portion 140 willbe in a left orientation such that upon threadedly engaging the removaltool 146 to the threaded portion 140, the user may continue to rotatethe removal tool 146 to the left side to disengage the distal end 112from the bone. Once the distal end 112 is disengaged from bone, the usermay pull the removal tool 146 proximally to draw the wire 104 out of thechannel 108.

In one exemplary embodiment, a portion of a driving tool engaging theengagement portion 138 may be sized and shaped to engage the shoulder154 of the channel 108 such that when the driving tool abuts theshoulder 154, the driving tool and thereby the wire 104 is preventedfrom being moved any further distally relative to the nail 102. Inanother embodiment, as shown in FIGS. 8 and 9A, the wire 104 may includea stop 156 proximal of the engagement portion 138 and the threadedportion 140, which extends radially outward and is sized and shaped toengage the shoulder 154. Thus, when the stop 156 abuts the shoulder 154,the wire 104 is prevented from moving any further distally relative tothe nail 102.

As shown in FIG. 10, an intramedullary device 200 according to a furtherembodiment of the present invention is substantially similar to theintramedullary device 100, but further comprises an insert 260 which maybe inserted into a channel 208 of an intramedullary nail 202 to preventa wire 204 passed therethrough from migrating proximally once it hasbeen inserted into the nail 202 to fix the nail 202 within a bone. Theinsert 260 may be sized and shaped to engage the channel 208. Forexample, the insert 260 may threadedly engage the proximal end of thechannel 208. The insert 260 may further include a groove 262 extendingtherealong from a proximal end 264 thereof sized and shaped to permit abone fixation element 226 to be inserted through a proximal locking hole224 of the nail 202 after insertion of the insert 260 in the channel208. Upon positioning of the wire 204 within the channel 208, asdesired, the insert 260 is inserted into the channel 208 proximally ofthe wire and positioned therein such that the groove 262 is aligned withthe proximal locking hole 224 of the nail 202. The insert 260 preventsthe wire 204 from moving proximally relative to the nail 202 while alsopermitting the bone fixation element 226 to be inserted through theproximal locking hole 224. An end cap 250, which may be substantiallysimilar to the end cap 150, may then engage the proximal end of thechannel 208 to prevent bone ingrowth within the channel 208.

As shown in FIG. 11, an intramedullary device 300 according to anotherembodiment of the present invention is substantially similar to theintramedullary device 200 described above except that the device 300comprises an insert 360 which does not include a groove. Rather, alength of the insert 360 is selected so that, once inserted into achannel 308 of an intramedullary nail 302, it does not interfere with aproximal locking hole 324 thereof. Thus, the insert 360 may be insertedinto the channel 308 proximally of a wire 304 while still permitting abone fixation element to be inserted through the proximal locking hole324, if desired. An end cap 350, which may be substantially similar tothe end caps 150, 250, may then be inserted into the proximal end of thechannel 308 to prevent bone ingrowth within the channel 308.

According to a surgical technique using the intramedullary device 100,the intramedullary nail 102 is inserted into a medullary canal of a bonealong a guide wire inserted into the medullary canal of the bone andreceived within the channel 108 as would be understood by those skilledin the art. Once the intramedullary nail 102 has been positioned withinthe medullary canal as desired, the guide wire may be removed and thenail 102 is fixed within the bone by inserting the wire 104 into thechannel 108. As described above, the wire 104 is inserted distally intothe channel 108 until the distal end 112 comes into contact with theramped surface 118 and is directed laterally out of the distal hole 106.As the distal end 112 passes through the distal hole 106 and comes intocontact with the bone, the wire 104 may be rotated, for example, using adriving tool engaging the engagement portion 138 of the wire 104. Asdescribed above, the wire 104 is inserted into the channel 108 until aportion of the driving tool or the stop 156 abuts the shoulder 154,preventing the wire 104 from being moved any further distally relativeto the nail 102. Thus, the distal end 112 is prevented from penetratingthe cortical wall. The self drilling tip 134 of the wire 104 permits thedistal end 112 to extend into the bone, thereby fixing the nail 102 andthe wire 104 relative thereto. It will be understood by those of skillin the wire 104′ may be used in a substantially similar manner as thewire 104.

Once the distal end 112 has been inserted into the bone, the bonefixation element 126 is inserted through the proximal opening 152 intothe proximal locking hole 124 to extend out of the nail 102 and engagethe surrounding bone, fixing the proximal end 114 of the nail 102 in adesired position relative to the bone. As described above, the bonefixation element 126 is inserted into the proximal hole 124 along thecentral axis thereof such that the shaft 128 of the bone fixationelement 126 extends at an angle relative to the longitudinal axis of thenail 102. Where there are additional locking holes along the nail 102,additional bone fixation elements may be guided and insertedtherethrough using a conventional aiming arm attached to the proximalend 114 of the nail 102. Once the intramedullary nail 102 has been fixedwithin the bone, the end cap 150 may be coupled to the proximal end 114of the nail 102. The end cap 150 may be received within the proximalopening 152 and rotated relative thereto to threadedly engage theproximal end 114 and close the proximal opening 152, thus preventingbone ingrowth therein. In addition, as shown in FIG. 8, a bone fixationelement 158 may be inserted through a proximal locking hole of the nail102 positioned proximally of the proximal end 132 of the wire 104 toprevent the wire 104 from migrating proximally relative to the nail 102once inserted to the desired position relative thereto. In anotherembodiment, as shown in FIG. 9, the end cap 150′ may be received withinthe proximal opening 152 such that the portion 151′ extends distallyinto the channel 108 proximally of the proximal end 132 of the wire 104.The portion 151′ thus prevents the wire 104 from migrating proximallywithin the channel 108 once inserted therein in the desired position.The end cap 150′ may, for example, be utilized when only distal lockingis required.

If, at any point, subsequent to the fixation the patient requiresremoval of the intramedullary nail 102, the end cap 150 may bedisengaged from the nail 102 and the bone fixation element 126 and/orthe bone fixation element 158 removed from the proximal hole 124. Thedistal end 148 of the removal tool 146 may be inserted into the channel108 to engage the threaded portion 140 of the wire 104. Once the removaltool 146 and the wire 104 have been coupled, the removal tool 146 may berotated, in an opposite direction required for driving the wire 104, todisengage the distal end 112 from the bone. The removal tool 146 maythen be drawn proximally relative to the nail 102 to pull the wire 104out of the channel 108 so that the nail 102 may be removed from thebone. It will be understood by those of skill in the art, however, thatthe distal end 112 of the wire 104 is only required to be drawn withinthe channel 108 to permit the intramedullary device 100 to be removedfrom the bone. A diameter of the distal end 112 is smaller than adiameter of the channel 108 such that distal end 112 does not contactthe channel 108 as it is drawn therein facilitating this withdrawal.

The intramedullay device 200 may be used in a manner substantiallysimilarly to the device 100, as described above. However, prior toinsertion of the bone fixation element 226 through the proximal lockinghole 224 and after insertion of the wire 204 in the desired position,the insert 260 is inserted into the channel 208 proximally of the wire204 to prevent the wire 204 from moving proximally relative to the nail202. The insert 260 is positioned such that the groove 262 is alignedwith the proximal locking hole 224 to permit the bone fixation element226 to be inserted therethrough. Upon insertion of the bone fixationelement 226, the end cap 250 may be coupled to the proximal end of thechannel 208. The intramedullary device 300 may be utilized in asubstantially similar manner to the intramedullary device 200, but doesnot require the insert 360 to be positioned in any particularorientation, as a length thereof is particularly selected such that theinsert 360 does not interfere with the proximal locking hole 324.

It will be apparent to those of skill in the art that variousmodifications and variations can be made in the structure and themethodology of the present invention, without departing from the spiritor scope of the invention. For example, any number of different distalholes and corresponding ramped surfaces may be provided (limited by thespace in the channel 108) to accommodate multiple wires 104 and,similarly, a plurality of proximal holes 124 may be included separatedfrom one another circumferentially about the longitudinal axis and/oralong the longitudinal axis as desired to accommodate a plurality ofbone fixation elements 126. Thus, it is intended that the presentinvention cover the modifications and variations of the inventionprovided that they come within the scope of the appended claims andtheir equivalents.

1-26. (canceled)
 27. A method for treating a bone, comprising: insertingan intramedullary nail into a medullary canal of a bone, theintramedullary nail extending along a longitudinal axis from a proximalend to a distal end; inserting a wire through a channel extendinglongitudinally through the nail until a distal end of the wire engages aramped surface along the channel and extends through an openingextending laterally through a wall of the nail opposite the rampedsurface; and rotating the wire in a first direction relative to the nailto drive the distal end of the wire into the bone.
 28. The methodaccording to claim 27, wherein inserting the intramedullary nail intothe medullary canal includes sliding the intramedullary nail along aguide wire received within the channel.
 29. The method according toclaim 27, further comprising inserting a bone fixation element through aproximal opening of the channel and into a lateral opening extendingthrough a wall at a proximal end of the nail such that a shaft of thebone fixation element extends along a central axis of the lateralopening, which is angled with respect to the longitudinal axis of thenail.
 30. The method according to claim 27, further comprising rotatingthe wire in a second direction relative to the nail to disengage thedistal end of the wire from the bone.
 31. The method according to claim30, further comprising pulling the wire proximally relative to the nailto remove the wire from the channel of the nail.